Modeling Rule v1.0

The day before a long weekend trip to the midwest, I realized I didn’t have a good travel sized drafting ruler. I wasn’t bringing a laptop, and haven’t found good drafting quality stand alone apps on the iPad, but still wanted to get a few designs down on paper, with enough detail and strict enough measurements to jump right to modeling later in the week.

After a few doodles, I had a good first pass at a simple and compact ruler for drafting 3D designs. It includes quarter circles, gap measures, a square edge, and 5mm notches across the 10 cm long side. The key feature: it was small, with very little detail, which made it quick to print. Fits snuggly into a bound notebook.



This version includes:

  • notches to measure 1mm, 2mm, 5mm, and 20mm gaps
  • 4 sizes of quarter circles
  • squaring angle
  • 100mm edge with tick marks at 5mm
  • square corner notch
  • quarter circle corner notch

As a first version it worked admirably well, but in practice some aspects of this design were less useful, others more useful. One significant drawback of this design (which will inform a follow up version 2) was the lack of discernable detail in low light conditions. Like on an evening flight.

This design and print were also good lessons in matching design dimensions with print quality. The design includes raised numbering for the tick marks, gaps, and arcs. When it came to printing, the numbering was too short – the print layer size was larger than the offset of the number from the plane of the ruler, so the numbering never got printed. Another adjustment for a later version.


  • text wasn’t tall enough, didn’t get printed
  • 5mm notches are hard to see in low light
  • right angle and curve notch-ins aren’t all that useful


  • Sizing insets for 1mm, 2mm, 5mm, 20mm work really well
  • Quarter circle insets are really helpful
  • Right angle of the largest quarter circle made a fantastic square edge
  • light and easy to wedge into (and keep in) a drawing pad, almost like a bookmark
  • clean edges made for good drafting quality and clean lines


Modeling Ruler v1.0

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